An example of a hand-held power tool having a component guided for linear movement is a rotary percussive drill in which hammer blows are imparted to a tool or a tool holder through the medium of a piston and ram combination movable relatively to a bearing support in the form of a guide tube cylinder in which the combination is located.
The guide cylinder is formed from a steel tube and has to be accurately sized. Additionally, holes have to be provided in the wall of the cylinder; these, of necessity, must be formed from outside the guide cylinder and this leaves burrs on the inside face of the cylinder wall. Such burrs are difficult to remove. The guide cylinder has also to be machined to accommodate a mechanism for reciprocating the piston combination relatively to the guide cylinder and this adds considerably to the production costs of the guide cylinder.